How to convert date format to timestamp in PHP

In PHP, it is often necessary to format or compare time. In fact, time exists in the computer in the form of a timestamp. A timestamp refers to the number of seconds from 0:00:00 on January 1, 1970 to the present. Therefore, in PHP, the conversion of time and timestamp is also very important. This article will focus on how to convert date format to timestamp in PHP.

PHP provides multiple date functions to facilitate date format conversion. Among them, the strtotime() function is the fastest, simplest, and most reliable way to convert any English text date format string into a UNIX timestamp.

1. strtotime() function

This function can convert a date and time format that can be understood by humans (such as: January 19 2022, 15:23) into a Unix timestamp (similar to 1642565012 ). strtotime() is the fastest, simplest, and most reliable way to convert any English text date format string into a UNIX timestamp.

The following is the syntax of the strtotime() function:

strtotime ( string $time [, int $now = time() ] ) : int

This function has two parameters: the first parameter is required and represents the date format string that needs to be converted into a timestamp; the second parameter is required. The two parameters are optional and represent the time base for conversion. The default is the current time.

The following is an example of using PHP to output the current time:

echo time(); //输出Unix时间戳
echo date('Y-m-d H:i:s'); //输出格式化时间

2. Date format example

When using the strtotime() function to convert the date format, you need to pay attention Date format correctness. Here are some commonly used date format examples:

Date format	Example
年	'2001', '15'
年-month	'2001-01', '15-01'
Year-Month-Day	'2001-01-01', '15-01-01'
Year-Month -Day:minute:second	'2001-01-01 15:00:00', '15-01-01 15:00:00'
Day of the week	'Monday', 'Tue'

You can pass the date string directly into the strtotime() function to get the corresponding timestamp. Below are some examples of using the strtotime() function to convert date formats.

//年月日转时间戳
echo strtotime("2022-01-19");

//年月日时分秒转时间戳
echo strtotime("2022-01-19 15:23:00");

For more information about timestamp and date format conversion, you can check out the PHP official documentation.

3. Summary

The strtotime() function provides a simple and fast way to convert date format to Unix timestamp, which can meet the needs of timestamp operations in PHP. When using this function to convert date formats, special attention needs to be paid to the correctness of the date string, otherwise the conversion will fail.

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